LAUSR

Background The functional prognosis of patients with carotid T occlusion is poor, but few comprehensive studies have investigated carotid non-T occlusion, in which the terminal internal carotid artery portion is unobstructed. We aimed to elucidate the clinical features of carotid non-T occlusion by comparing patients with acute carotid T occlusion and carotid non-T occlusion. Methods Among 362 patients who underwent thrombectomy between January 2015 and June 2018, 20 and 61 were diagnosed with carotid non-T occlusion and carotid T occlusion, respectively. We compared preoperative clinical findings, treatment strategies, treatment complications and functional outcomes between the two groups. Results Age, sex, preoperative National Institutes of Health stroke scale, cerebral infarction subtypes and medical history did not significantly differ. In contrast, preoperative diffusion-weighted imaging–Alberta Stroke Program early computed tomography scores were 9 (1–11) and 6.5 (0–11) for the carotid non-T occlusion and carotid T occlusion groups, respectively (P = 0.015). The duration of treatment or the median number of passes (2.5 vs. 2.0), the numbers of patients with thrombolysis in cerebral infarction 2b/3, bleeding complications and modified Rankin scale scores of 0–2 on postoperative day 90 did not significantly differ between the two groups. Manual aspiration before, internal carotid artery arrest while crossing a lesion and injection into the contralateral side were significantly more frequent in patients with carotid non-T occlusion. Intracranial internal carotid artery stenosis was significantly more frequent in patients with carotid non-T occlusion (n = 4, 20%) than carotid T occlusion (n = 0), and 10% of patients with carotid non-T occlusion had arterial dissection. Conclusion Patients with carotid non-T occlusion more frequently had a background of intracranial internal carotid artery stenosis or arterial dissection than patients with carotid T occlusion. Specific treatment strategies should be developed to improve the clinical outcomes of patients with carotid non-T occlusion.